Compact manifolded fail safe hydraulic control system

ABSTRACT

A manifolded fail-safe hydraulic control system provides fail-safe operation of a pipeline valve using no more than a total of 45 proprietary parts in the system. The system controls the operation of a spring return actuator, which in turn strokes the pipeline valve from the normal operating position to the fail-safe position, or from the fail-safe position to the normal operating position. The system enables the valve to automatically stroke to its fail-safe position without external power.

CROSS-REFERENCE TO PRIOR APPLICATIONS

This application claims benefit to Canadian Patent Application No. 2,535,326, filed Nov. 18, 2005 and entitled “Compact Manifolded Fail Safe Hydraulic Control System”.

1. Field of the Invention

The present invention relates to the automation of pipeline valves used in critical fail-open or fail-close applications.

2. Background of the Invention

Currently there are existing self contained emergency shut down systems sold by Emerson Process Management (No known patent, Bettis service manual # I-0019 Rev 4 and Bettis catalog # 45.00), Wood Group (U.S. Pat. No. 5,291,918 and U.S. Pat. No. 5,070,900 and U.S. Pat. No. 5,213,133), Stream-Flo Industries (No known patent, Steam-Flo catalog # 05/03) and Argus Machine Company (CD Patent 2,266,806, Argus catalog # 5000-1-3000-01/02). All of these systems are designed to control the emergency shut down closure of valves on oil and gas wellheads. Typically these systems are designed with a significantly larger number of proprietary components. A larger total number of proprietary components used in the cited emergency shut down systems leads to unreliability.

BRIEF SUMMARY OF THE INVENTION

The new Manifolded Fail Safe Hydraulic Control System provides an incremental improvement in reliability due to it's simple reliable design configuration. It is ideal for controlling critical fail-open and fail-close pipeline valves. Critical applications require that the pipeline valve does stroke to the fail-safe position without the need for an external power source. Fail-open applications include fire protection, pressure relief, process balance. Incorporating a compact oil immersed hydraulic power pack within the reservoir provides an incremental improvement in operating convenience.

The simple and compact Manifolded Fail Safe Hydraulic Control System represents a new and useful improvement to the typical hydraulic ESD system which are currently being sold. It's superior reliability and compact size make it ideal for critical applications other than oil and gas wellheads. Instead of the typical arrangement where each control device is assembled in it's own pressurized body, control devices are assembled into one common pressurized manifold. Total number of proprietary parts compared to existing emergency shutdown systems are minimized to increase reliability.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention will now be described in further detail. Other features, aspects, and advantages of the present invention will become better understood with regard to the following detailed description, appended claims, and accompanying drawings (which are not to scale) where:

FIG. 1 is a schematic drawing of the hydraulic fail safe control system with the 2-way regulated dump valve.

FIG. 2 is a schematic drawing of the hydraulic fail safe control system with the 2-way high pressure dump valve.

FIG. 3 is a outline drawing of the manifolded fail safe hydraulic control system. FIG. 4 is a outline drawing of the hand pump lever.

FIG. 5 is a cross section drawing of the hand pump and reservoir.

FIG. 6 is a cross section drawing of the reservoir with oil immersed hydraulic power supply.

FIG. 7 is a cross section drawing of the manifolded regulator without system pressure.

FIG. 8 is a cross section of the manifolded regulator with system pressure.

FIG. 9 is a cross section of the manifolded accumulator without system pressure.

FIG. 10 is a cross section of the manifolded accumulator with system pressure.

FIG. 11 is a cross section of the manifolded low pressure relief valve without system pressure.

FIG. 12 is a cross section of the manifolded low pressure relief with system pressure.

FIG. 13 is a cross section of the manifolded high pressure relief valve without system pressure.

FIG. 14 is a cross section of the manifolded high pressure relief with system pressure.

FIG. 15 is a cross section of the manifolded regulated 2-way dump valve in the dumped position.

FIG. 16 is a cross section of the manifolded regulated 2-way dump valve in the leveled position.

FIG. 17 is a cross section of the manifolded regulated 2-way dump valve in the charged position.

FIG. 18 is a cross section of the manifolded high pressure 2-way dump valve in the dumped position.

FIG. 19 is a cross section of the 3-way high and low pressure pilot with 0.562″ sensing piston.

FIG. 20 is a cross section of the 3-way high and low pressure pilot with 0.312″ sensing piston.

FIG. 21 is a cross section of the 3-way high and low pressure pilot with 1.125″ sensing piston.

FIG. 22 is a cross section pressure pilot 3-way spool and sleeve near middle operating position.

FIG. 23 is a cross section pressure pilot 3-way spool and sleeve at low sensed pressure position

FIG. 24 is a cross section pressure pilot 3-way spool and sleeve at high sensed pressure position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

The compact manifolded hydraulic fail safe control system is used to control the operation of a spring return actuator which in turn strokes the pipeline valve from the normal operating position to the fail safe position, or from the fail safe position to the normal operating position. The 2-way dump valve opens to circulate the spring return actuator's cylinder volume to the reservoir. The pipeline valve will automatically stroke to the required fail-safe position Without an external power source. Pipeline valves operated with quarterturn or linear type spring return actuators can be operated using the manifolded hydraulic fail safe control system. The 2-way dump valve is opened when the regulated signal pressure is removed. The manifolded hydraulic fail safe control system incorporates a regulated signal pressure circuit and a pressure circuit maintained at the actuator operating pressure.

The regulated signal pressure to the 2-way dump valve is removed when pipeline pressure exceeds the 3-way pressure pilot's high or low set-point. Likewise the 2-way dump valve regulated signal pressure is removed when the 3-way S.C.A.D.A. valve receives a signal. When the 2-way dump valve is opened the spring return actuator cylinder volume is circulated to the reservoir across the regulator (pressure regulated cylinder dump) or across a diffuser (high-pressure cylinder dump).

High pressure and low-pressure relief valves are used to limit system pressure upstream and downstream of the regulator. A low-pressure accumulator is provided to accommodate ambient temperature fluctuations.

The hydraulic fail-safe control system can be reset, or “re-charged”, by hand pumping in order to refill the spring return actuator cylinder volume and return the pipeline valve to it's noanial operating position. The 2-way dump valve's lever is first rotated to the horizontal plane, from the vertical plane. Then the manual hand pump is cycled until the spring return actuator and pipeline valve have returned to their normal operating positions. Alternatively an electrically powered pump enclosed in the reservoir can also be used to reset the system.

The system is reset when the 2-way dump valve's latch lever automatically repositions itself in the vertical plane and the line valve is in the normal operating position. When reset the system is able to monitor pipeline pressure and process conditions. The pipeline valves' fail-safe valve position can he achieved manually by applying axial hand force to the 2-way dump valve lever. This hand force acts against 2-way dump valve internal pressure to manually open the dump valve.

All of the fail-safe hydraulic control system proprietary components are assembled and/or installed into a single pressurized manifold.

Turning now to the drawings wherein like reference characters indicate like or similar parts throughout, FIG. 1 illustrates a closed hydraulic circuit to control the operation of a fail safe pipeline valve. The hydraulic circuit consists of two loops. The first loop is connected to the spring return actuator cylinder volume and is at high pressure. The second loop is at low pressure and is connected to the first loop across the low pressure regulator 5. The low pressure regulator 5 supplies the low pressure accumulator 8 with a volume of low pressure hydraulic fluid from first loop. The low pressure relief valve 7, 2-way dump valve 9, 3-way SCADA valve 11 and 3-way pressure pilot 10 are part of the second loop and recirculate return hydraulic fluid back to the reservoir 12. The low pressure accumulator 8 spring volume is connected to the return lines and the reservoir 12 fill port. There is a hand pump 1, filter and check valve module 2 and high pressure relief valve 4 on the first loop.

Referring to FIG. 1 the outline of the manifold is shown to illustrate that the hand pump 1, low pressure regulator 5, pressure accumulator 8, low pressure relief valve 7, high pressure relief valve 4 and the regulated 2-way dump valve 9 are assembled within the single one piece manifold.

Referring to FIG. 2 there is shown another version of the closed hydraulic circuit. In the second hydraulic circuit shown in FIG. 2 the 2-way dump valve 14 connects to the first high pressure loop. In FIG. 1 the spring return actuator cylinder volume is regulated to low pressure before it is dumped to the reservoir 12. In FIG. 2 the spring return actuator cylinder volume is dumped directly to the reservoir through a diffuser.

Referring to FIG. 3 there is shown a top view, front view and side view of the compact manifolded hydraulic fail safe control system. The rectangular reservoir profile matches the profile of the manifold thereby maximizing the useful volume in the reservoir. The front profile of the reservoir shows the sloped bottom provided to collect solid debris adjacent to the drain port and away from the hand pump inlet screen.

Referring to FIG. 4 there is shown in profile a side view of the compact manifolded hydraulic fail safe control system with hand pump handle 21 placed in the hand pump lever 22. In order to cycle the hand pump the handle 21 is placed into the lever 22. Three operating positions are provided for the lever 22. The lever 22 pivots about a bolt engaged in the lever plate 23. A second bolt in the lever engages the circular bolt pattern in the lever plate 23 which includes three holes equally spaced at sixty-degrees inclusive.

Referring to FIG. 5 there is shown a cross section drawing of the hand pump which is assembled into the manifold 20 using an additional nine proprietary parts. The piston 24 cycles in the horizontal plane. In order to reduce operating friction and minimize eccentric loading of the seals the piston 24 cycles within a standard plastic bushing. The lever 22 has two holes which intersect at 90 degrees and are provided to accept the handle 21. The handle 21 is bolted to the lever 22 in a bolt hole located at this intersection. This said 90 degrees combined with 60 degrees of rotary adjustment referenced in FIG. 4 results in 150 degrees of total handle 21 adjustment. The module 27 contains the hand pump discharge filter and check valve referenced in FIG. 1. The module 27 assembly complete with said discharge filter and check valve can be removed and replaced as a cartridge. The module 27 assembly includes an elevated pipe plug in order to provide an effective method of venting entrained air from the compact manifolded hydraulic fail safe control system. When the link 25 is loaded in tension there are no resulting bending stresses only simple tension stresses and contact stresses.

Referring to FIG. 6 there is shown in profile a side view of the compact oil immersed hydraulic power supply 30. The compact oil immersed hydraulic power supply 30 replaces the manual hand pump and is enclosed within the reservoir 29 and manifold 20.

Referring to FIG. 7 there is shown a cross section drawing of the low pressure regulator which is assembled into the manifold 20 using four additional proprietary parts. The piston 42 and poppet 43 are plastic. The piston has a slot cut across and through the small end which has the pin hole. The poppet 43 has four linear radially profiled slots along it's entire axial length. The poppet 43 has four axial grooves running the entire length and equally spaced around the outside diameter. The plate 41 contains a stack of spring washers. A set screw threads through the cover 40 and is used to adjust spring load when torqued against the plate 41.

Referring to FIG. 8 the poppet 43 seals directly against the manifold 20 when it is in the closed position. When the piston 42 compresses the stack of spring washers the poppet 43 contacts the mating sealing edge provided in the manifold 20. A spacer pin maintains separation between the poppet 43 and the piston 42. The plastic piston reduces friction forces in the low pressure accumulator. A tapped hole is provided in the top end of the piston 42 to aid with disassembly.

Referring to FIG. 9 there is shown a cross section drawing of the low pressure accumulator which is assembled into the manifold 20 using two additional proprietary parts. The cover 50 positions the piston 51 starting position. The plastic piston 51 reduces friction forces in the low pressure accumulator. A tapped hole is provided on the front end of the piston 51 to aid disassembly. A single spiral groove circles the top end of the piston 51 approximately three times to ensure evenly distributed pressure when the piston 51 is in it's starting position.

Referring to FIG. 10 there is shown a cross section drawing of the low pressure accumulator in the pressurized condition. The back end of the piston 51 does not contact the manifold in normal operation. The low pressure accumulator has large capacity which is required for the large displacement generated by the 2-way dump valve's large piston area shown in FIG. 15.

Referring to FIG. 11 there is shown in cross section drawing of the low pressure relief valve which is assembled into the manifold 20 using four additional proprietary parts. The bushing 62 is plastic to reduce friction forces. The seat 61 mates against the manifold 20 to form the poppet seal groove. The seat 61 is fixed in position by a retaining ring. The poppet 60 mating surface contacts the seat 61 mating surface. Four holes drilled through and normal to the poppet 60 mating surface intersect the chamfer provided on the seat 61 mating surface to form the volume which is common to the reservoir. The cap 63 is provided with a hex hole and is used to adjust spring load on the single coil spring. The cap 63 is common to the low pressure and high pressure relief valves shown in FIG. 11 and FIG. 13.

Referring to FIG. 12 there is shown a cross section drawing of the low pressure relieve valve in the open position. A hole drilled through the cap 63 discharges fluid into the reservoir.

Referring to FIG. 13 there is shown a cross section drawing of the high pressure relief valve which is assembled into the manifold 20 using four additional proprietary parts. The bushing 72 is plastic to reduce friction forces. The seat 71 mates against the manifold 20 to form the poppet seal groove. The poppet 70 mating surface contacts the seat 61 mating surface. Four holes drilled through and normal to the poppet mating surface intersect the chamfer provided on the seat mating surface to form the volume which is common to the reservoir. The cap 73 is provided with a hex hole and is used to adjust spring load on the stack of spring washers.

Referring to FIG. 14 there is shown a cross section drawing of the high pressure relieve valve in the open position. A hole drilled through the cap 73 discharges fluid into the reservoir.

Referring to FIG. 15 there is shown a cross section drawing of the regulated 2-way dump valve which is assembled into the manifold 20 using six additional proprietary parts. In FIG. 15 it is shown in the “dumped” position. In the “dumped” position the lever 80 is vertical and against the standard washer. The standard washer 82 and sleeve 84 are plastic to reduce friction forces. The one piece plunger 85 has a seal on it's outside diameter located within an annular groove adjacent to a male curved conical surface. The sleeve 84 is fixed in the axial position by the cover 88. In the “dumped” position the plunger 85 seal is open and not contained in the sleeve 84 bore. In the “dumped” position the lever 80 is vertical and against the standard washer.

Referring to FIG. 16 there is shown a cross section drawing of the regulated 2-way dump valve which is assembled into the manifold 20 using six additional proprietary parts. In FIG. 16 it is shown in the “leveled” position. The lever 80 has a radial profile with a flat rectangular surface on the end which contacts the standard washer as the lever 80 is rotated 90° to the level and horizontal position. The lever 80 pivots on a spring pin installed through a clearance hole in the lift 81 and a mating hole in the lever 80. The said mating hole in the lever 80 is located off center relative to said radial profile. This said pin location effectively creates cam geometry. The plunger 85 threads into the lift 81 between which is the clamped the piston 84. The said rotation of the lever 80 to the level position results in the lift 81, piston, 84 and plunger 85 moving and compressing the single coil spring. The lever 80 is held in the level position by the spring compression and the flat rectangular surface. The male curved conical surface gradually enters the female sleeve 87 as the lever 80 is moved to the “leveled” position. In the “leveled” position the plunger 85 seal is fully contained in the female sleeve 87 bore.

Referring to FIG. 17 there is shown a cross section drawing of the regulated 2-way dump valve which is assembled into the manifold 20 using six additional proprietary parts. In FIG. 17 it is shown in the “charged” position. Application of the regulated signal pressure further compresses the single coil spring and the plunger 85 seal further enters into the female sleeve 87. In the “charged” position the lever 80 has automatically pivoted and dropped from the level horizontal position to the vertical position. In the “charged” position the said plunger 85 seal remains within the sleeve 84 bore. The plunger 85 seal is exposed to fluid velocity as it moves from the “charged” position to the “dumped” position in FIG. 15. During this transition the plunger 85 seal leaves the sleeve 84 bore and the regulated pressure contained by the plunger 85 seal is released. During this transition the male curved conical profile immediately creates a widening annular flow passage reducing fluid velocity across said plunger 85 seal.

Referring to FIG. 18 there is shown a cross section drawing of the high pressure 2-way dump valve which is assembled into the manifold 20 using seven additional proprietary parts. In FIG. 15 it is shown in the “dumped” position. In the “dumped” position the lever 80 is vertical and against the washer 82. The lever 80, lift 81, standard washer, cover 82 and piston 83 are common to the regulated 2-way dump valve in FIG. 15. The spool 92 has a male conical seal surface. The plastic sleeve 91 is axially contained against a stack of spring washers by the plastic nut 90. In the “dumped” position the said spool 92 male seal surface is open and does not contact the sleeve 91 bore. In the “dumped” position the spring washer stack is only just free. The high pressure 2-way dump valve “leveled” and “charged” positions function the same as the regulated 2-way dump valve shown FIG. 16 and FIG. 17. The same manifold 20 can be assembled with either the regulated 2-way dump valve shown in FIG. 15 or the high pressure 2-way dump valve shown in FIG. 18.

Referring to FIG. 19 there is shown a 3-way pressure pilot with 0.562″ diameter piston 101 which is assembled using fourteen proprietary parts. The sleeve 104, standard low spring washer and standard high spring washer are plastic to reduce friction forces. The piston orifice 100 protects the piston 101 and piston seals. The piston 101 low and high movement is fully constrained by the body 102 and piston orifice 100. The spool 103 which utilizes a socket hex pipe plug contacts the piston 102. The piston 101 moves up and down with pipeline pressure and thereby moves the spool 103 relative to the sleeve 104. The spool 103 is always in contact with the low spring saddle 112. The low spring saddle 112 is always in contact with the standard low spring washer and low spring. The sleeve 104 is fixed in the axial position within the body 102 by the spacer ring 105 and retaining ring. The body 102 utilizes two hex socket pipe plugs to create the common exhaust volume. The spring canister 106 threads onto the body 102 to engage a mating shoulder. The high spring saddle 111 contacts the top body 102 surface unless high pressure has moved up piston 101, spool 103 and low spring saddle 112 further compressing the low spring and creating surface engagement between the low spring saddle 112 and high spring saddle 111. The resulting engagement also results in further compression of the high spring. The low spring and high spring are located within the spring canister 106 and contact the standard low spring washer and standard high spring washer. The low spring plate 110 is located on top of the low spring. The spring nut 109 threads into the spring canister 106. The low spring screw 108 threads into the spring nut 109. Spring adjustment is achieved by first adjusting the spring nut 109 and secondly adjusting the low spring screw 108. The spring nut 109 is provided with tapped holes to aid in adjustment and disassembly. The spring cap 107 threads onto the spring canister 106 to engage a mating shoulder. In a hole common to the volume formed between the piston 101 seals and spool 103 seals the body 102 utilizes a ball coil spring, ball and vent orifice 113. The said common volume will exhaust any excess pressure or seal leakage to atmosphere or to an exhaust line.

Referring to FIG. 20 there is shown a 3-way pressure pilot with 0.312″ diameter piston 101 which is assembled using seventeen proprietary parts. All proprietary parts are common to the 3-way pressure pilot with 0.562″ diameter piston shown in FIG. 20 except for piston orifice 114, piston 115 and body 116.

Referring to FIG. 21 there is shown a 3-way pressure pilot with 1.125″ diameter piston 101 which is assembled using seventeen proprietary parts. All proprietary parts are common to the 3-way pressure pilot with 0.562″ diameter piston shown in FIG. 20 except for piston orifice 117, piston 118 and body 119.

Referring to FIG. 22 there is shown in detail the 3-way pilot with the spool 103 centered in the sleeve 104 with normal pipeline pressure. The spool 103 has four annular grooves into which are installed seals. The spool 103 is cross drilled to formed a common volume between the two center spool seals and the plugged end. The sleeve 104 has a series of three annular cavities formed by four seal grooves on the outside diameter into which are installed seals. These three annular sleeve 104 cavities are conjoined with three annular seal grooves on the inside diameter formed by four annular grooves into which are installed seals. With normal pipeline pressure the two outer spool 103 seals are not contained within the sleeve 104 bore. The two outer spool 103 seals are common with the port labeled EXH. The body port labeled IN is common with the body port labeled OUT, and the port labeled EXH is closed. With low pressure the spool 103 moves down to the position shown in FIG. 23. With high pressure the spool 103 moves up to the position shown in FIG. 24.

Referring to FIG. 23 there is shown in detail the 3-way pilot with the spool 103 positioned in the sleeve 104 with low pipeline pressure. The spool 103 seal located second from the pipe plug end is not contained within the sleeve 104 bore. This spool seal is common with the port labeled EXH. The body port labeled IN is closed. The body port labeled OUT is common with the port labeled EXH. When this spool seal is moving to the position shown it leaves the sleeve 104 bore to immediately enter a volume formed with a 30 degree entry which reduces fluid velocity across it.

Referring to FIG. 24 there is shown in detail the 3-way pilot with the spool 103 positioned in the sleeve 104 with high pipeline pressure. The spool 103 seal located third from the pipe plug end is not contained within the sleeve 104 bore. This spool seal is common with the port labeled EXH. The body port labeled IN is closed. The body port labeled OUT is common with the port labeled EXH. When this spool seal is moving to the position shown it leaves the sleeve 104 bore to immediately enter a volume formed with a 30 degree entry which reduces fluid velocity across it.

The foregoing description details certain preferred embodiments of the present invention and describes the best mode contemplated. It will be appreciated, however, that changes may be made in the details of construction and the configuration of components without departing from the spirit and scope of the disclosure. Therefore, the description provided herein is to be considered exemplary, rather than limiting, and the true scope of the invention is that defined by the following claims and the full range of equivalency to which each element thereof is entitled. 

1. A manifolded fail-safe hydraulic control system for controlling fail-safe operation of a pipeline valve, said system comprising: a pump; a pressure regulator; a low pressure accumulator; a low pressure relief valve; a high pressure relief valve; and a two-way regulated dump valve; wherein said system is operable to place the pipeline valve in a fail-safe position using no more than a total of 45 proprietary parts in the system. 